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A 2009 crash involving Colgan Air involved pilot fatigue, an investigation found

"Safety is the top priority at Colgan," a spokesman says

The Federal Aviation Administration wants to fine commuter jet operator Colgan Air for flying planes three years ago without giving crew members enough rest.

In a letter to the airline released Friday, the FAA lays out 17 instances in which pilots or flight attendants flew without the required amount of off-duty rest time. It proposes a fine of $153,000.

FAA regulations require the airline to give each crew member 24 consecutive hours off every seven days.

The FAA says that between June 14, 2008, and February 23, 2009, Colgan scheduled flight duty time for two captains, two first officers and six flight attendants on a seventh day after they had been on duty for the previous six days.

The FAA said one of the captains operated four flights without adequate rest. Each of the other flight crew members operated one flight without meeting this rest requirement.

Crews are also required to get time off after eight hours of flying. The FAA says that in 2008 Colgan had three flight attendants and one first officer work without this required time off.

"Colgan's actions in assigning flight crew members and flight attendants to duties in scheduled air transportation without required rest ... were careless or reckless so as to endanger the lives and property of others," writes Christian Lewerenz, an attorney for the FAA in the letter to Colgan.

Last year, the FAA proposed fining Colgan nearly $1.9 million for allegedly allowing 84 flight attendants to fly for a week after the airline was informed they had been trained on fire extinguishers that were different from those used on their aircraft.

In 2009, Colgan Air Flight 3407 crashed near Buffalo, New York, killing 50 people. The National Transportation Safety Board report on the crash cited pilot error as a factor, adding, "the pilots' performance was likely impaired because of fatigue, but the extent of their impairment and the degree to which it contributed to the performance deficiencies that occurred during the flight cannot be conclusively determined."

One of the crew rest violations cited Friday by the FAA took place the day after the crash.

"Safety is the top priority at Colgan," wrote Joe Williams, spokesman for parent company Pinnacle Airlines in a statement to CNN. "The proposed fine is based on actions that occurred more than three years ago. We believe we complied with all applicable duty and rest rules and will respond accordingly."

The airline has 30 days to reply to the FAA.

The FAA in December announced new pilot flight, duty and rest rules that will go into effect in December 2013.

Colgan is a subsidiary of Pinnacle Airlines and flies small commuter jets for US Airways Express, United Express and Continental Connection.